One document matched: draft-ietf-acap-spec-03.txt
Differences from draft-ietf-acap-spec-02.txt
Network Working Group C. Newman
Internet Draft: ACAP Innosoft
Document: draft-ietf-acap-spec-03.txt J. G. Myers
Expire in six months March 1997
ACAP -- Application Configuration Access Protocol
Status of this Memo
This document is an Internet Draft. Internet Drafts are working
documents of the Internet Engineering Task Force (IETF), its Areas,
and its Working Groups. Note that other groups may also distribute
working documents as Internet Drafts.
Internet Drafts are draft documents valid for a maximum of six
months. Internet Drafts may be updated, replaced, or obsoleted by
other documents at any time. It is not appropriate to use Internet
Drafts as reference material or to cite them other than as a
``working draft'' or ``work in progress``.
To learn the current status of any Internet-Draft, please check the
1id-abstracts.txt listing contained in the Internet-Drafts Shadow
Directories on ds.internic.net, nic.nordu.net, ftp.isi.edu, or
munnari.oz.au.
This document suggests a proposed protocol for the Internet
community, and requests discussion and suggestions for improvements.
Distribution of this draft is unlimited.
The protocol discussed in this document is experimental and subject
to change. Persons planning on either implementing or using this
protocol are STRONGLY URGED to get in touch with the author before
embarking on such a project.
Abstract
The Application Configuration Access Protocol (ACAP) is designed to
support remote storage and access of program option, configuration
and preference information.
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Table of Contents
Status of this Memo ............................................... i
Abstract .......................................................... i
ACAP Protocol Specification ....................................... 1
0. Changes from version -01 to version -02 .................. 1
0.1. Changes from draft -02 to draft -03 ...................... 2
0.2. Open Issues .............................................. 4
1. Conventions Used in this Document ........................ 4
2. Protocol Overview ........................................ 5
2.1. Link Level ............................................... 5
2.2. Commands and Responses ................................... 5
2.2.1. Client Protocol Sender and Server Protocol Receiver ...... 5
2.2.2. Server Protocol Sender and Client Protocol Receiver ...... 6
2.3. State and Flow Diagram ................................... 7
2.3.1. Non-Authenticated State .................................. 7
2.3.2. Authenticated State ...................................... 7
2.3.3. Logout State ............................................. 7
2.4. Operational Considerations ............................... 8
2.4.1. Untagged Status Updates .................................. 8
2.4.2. Response when No Command in Progress ..................... 8
2.4.3. Autologout Timer ......................................... 8
2.4.4. Multiple Commands in Progress ............................ 9
2.5. Datasets and Entries ..................................... 9
2.6. Predefined Attributes .................................... 9
2.7. Attribute metadata ....................................... 10
2.8. Operational Command Overview ............................. 11
3. Protocol Elements ........................................ 11
3.1. Data Formats ............................................. 12
3.1.1. Atom ..................................................... 12
3.1.2. Number ................................................... 12
3.1.3. String ................................................... 12
3.1.3.1. 8-bit and Binary Strings ................................. 13
3.1.4. Parenthesized List ....................................... 13
3.1.5 NIL ...................................................... 13
3.2. ACAP URL scheme .......................................... 13
3.2.1. ACAP URL User Name and Authentication Mechanism .......... 14
3.2.2. Relative ACAP URLs ....................................... 15
3.3. Contexts ................................................. 15
3.4. Orderings ................................................ 15
3.5. Server Status Responses .................................. 16
3.6. Server Command Continuation Request ...................... 17
4. Protocol Specification ................................... 19
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4.1. Initial Connection ....................................... 19
4.1.1. ACAP Untagged Response ................................... 19
4.2. Any State ................................................ 20
4.2.1. NOOP Command ............................................. 20
4.2.2. LOGOUT Command ........................................... 21
4.2.3. OK Response .............................................. 21
4.2.4. NO Response .............................................. 21
4.2.5. BAD Response ............................................. 22
4.2.6. BYE Untagged Response .................................... 22
4.3. Non-Authenticated State .................................. 23
4.3.1. AUTHENTICATE Command ..................................... 23
4.4. Searching ................................................ 25
4.4.1. SEARCH Command ........................................... 25
4.4.2. ENTRY Intermediate Response .............................. 29
4.4.3. MODTIME Intermediate Response ............................ 29
4.4.4. REFER Intermediate Response .............................. 29
4.5. Contexts ................................................. 30
4.5.1. FREECONTEXT Command ...................................... 30
4.5.2. UPDATECONTEXT Command .................................... 30
4.5.3. ADDTO Untagged Response .................................. 31
4.5.4. REMOVEFROM Untagged Response ............................. 31
4.5.5. CHANGE Untagged Response ................................. 32
4.5.6. MODTIME Untagged Response ................................ 32
4.6. Dataset modification ..................................... 32
4.6.1. STORE Command ............................................ 33
4.6.2. DELETEDSINCE Command ..................................... 34
4.6.3. DELETED Intermediate Response ............................ 34
4.7. Access Control Lists ..................................... 34
4.7.1. SETACL Command ........................................... 36
4.7.2. DELETEACL Command ........................................ 37
4.7.3. MYRIGHTS Command ......................................... 37
4.7.4. MYRIGHTS Intermediate Response ........................... 38
4.7.5. LISTRIGHTS Command ....................................... 38
4.7.6. LISTRIGHTS Intermediate Response ......................... 38
4.8. Quotas ................................................... 39
4.8.1. SETQUOTA Command ......................................... 39
4.8.2. GETQUOTA Command ......................................... 40
4.8.3. QUOTA Intermediate Response .............................. 40
4.9. Extensions ............................................... 40
5. Dataset Management ....................................... 41
5.1. Dataset Inheritance ...................................... 41
5.2. Dataset attributes ....................................... 41
6. Namespace conventions .................................... 42
6.1. Dataset Namespace ........................................ 42
6.2. Attribute Namespace ...................................... 42
7. Registration procedures .................................. 42
7.1. Ordering Functions ....................................... 43
7.2. ACAP Capabilities ........................................ 43
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7.3. Dataset Classes .......................................... 44
7.4. Private Attribute Subtree ................................ 44
8. Formal Syntax ............................................ 45
9. Security Considerations .................................. 53
10. Authors' Addresses ....................................... 53
Appendices ........................................................ 54
A. References ............................................... 54
B. ACAP Keyword Index ....................................... 55
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ACAP Protocol Specification
0. Changes from version -01 to version -02
1) Added reference to definitions of MUST, SHOULD, etc.
2) Removed last mention of "NIL".
3) Renamed "name" to "entry".
4) Datasets are ordered in a server-determined manner.
5) "acl" metadata is read-only.
6) return error on fetch of undefined metadata.
7) Added "subdataset" attribute and discussion of dataset hierarchy.
8) Changed "request response" to "request", and "result response" to
"result" to simplify the text.
9) Removed "Child Dataset Attributes" and added "Operational Command
Overview"
10) Restructured document a bit, adding a "protocol elements" section
11) Added "*" rule to the RETURN search modifier.
12) Added the DEPTH search modifier.
13) Added predefined orderings.
14) Added ACAP URL scheme
15) Removed NOTIFYCONTEXT command, added NOTIFYCONTEXT search
modifier.
16) DELETEDFROM -> intermediate DELETED response
17) Added second argument to LIMIT search modifier.
18) Added "[" and "]" to atom_specials to deal with special
information tokens cleanly; removed "*" and "%"
19) made resp_text into quoted string to simplify parsing.
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20) Added SASL list to Capability greeting.
21) Removed ACL, LISTRIGHTS, GETACL, NOACL in favor of dataset
management attributes
22) Added AND to SEARCH keys and removed parentheses around SEARCH
keys.
23) simplified MYRIGHTS command and result
24) Simplified STORE and DELETE using entry-path
25) Remove locking of entire dataset. Add MODTIME intermediate
result to LOCK command.
26) Added GETQUOTA and SETQUOTA.
27) Astring is removed from the grammar, except for LOGIN.
28) Changed term "shadow" to "inherit"
29) Added dataset management section
30) Added sort-hint
31) Added QUOTA and PERMISSION response codes
32) Added registration procedures
33) Added dataset namespace conventions
34) TOOMANYCONTEXTS -> TRYFREECONTEXT
0.1. Changes from draft -02 to draft -03
1) Removed sort-hint, LOGIN, createtime, DELETE, LOCK, UNLOCK. DUMB
SASL mechanism will be defined in a separate document.
2) Put NIL back in.
3) Changed STORE command to allow NIL, include conditional store, and
store multiple entries atomically.
4) Fleshed out "extensions" section a bit.
5) Used parenthesis instead of brackets for special information
tokens. Simplifies parsing. Took "[" and "]" back out of atom
specials.
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6) *Changed quoted string to allow UTF-8 characters.
7) kilobytes -> octets
8) Added "time" field to the RANGE search modifier to remove
ambiguity problems with unsolicited notifications.
9) Clarified that a BAD completion result must be returned for a
number of cases (bad metadata, invalid search modifier combinations,
etc).
10) Updated example in ACAP URL section and added rest of description
for the <url-filter> element.
11) Clarified octet collation.
12) Clarified REFER response code. Added REFER intermediate response
to SEARCH.
13) Clarified DEPTH search modifier.
14) Forbid use of "*" in attribute name. Forbid entry name from
beginning with ".".
15) Finished changing "NOTIFYCONTEXT command" to "NOTIFYCONTEXT
search modifier".
16) Changed ACL identifier to permit UTF-8.
17) Added reference to US-ASCII.
18) private. -> vnd. and prs.
19) permit multiple arguments to a capability.
20) Put back LISTRIGHTS command and response.
21) Added "ALL" search key, "HARDLIMIT" search modifier and
"WAYTOOMANY" response code.
22) Allow STORE with no attributes added; SHOULD/MUST rules as
appropriate.
23) Clarify inheritance rules with respect to modtime attribute and
ACL attributes.
24) Added rule about UPDATECONTEXT returning MODTIME if changes.
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25) Clarify that ADDTO/REMOVEFROM/CHANGE renumber other entries in
the context.
26) Added editorial clarity note to section 1.
27) Require MODTIME response to successful SEARCH.
28) Allow size to be 0 in value<origin.size>.
0.2. Open Issues
1) Document structure: do you like it?
2) Need to define precise Unicode-based ordering function, if one
exists that isn't a nightmare to implement. If it is a nightmare to
implement, we can make it a SHOULD rather than a MUST.
3) Consider making ACL model more precise. Would like to pick AFS
semantics over POSIX semantics since AFS semantics are more
intuitive. Need to confer with security area director. Currently
both ACL semantics are permitted.
4) Current namespace conventions make certion useful operations
difficult. Other simple conventions appear worse. Need a way to
permit both "list all shared addressbooks" and "list all datasets
owned by this user". Ideas include multiple namespaces (e.g.,
"/addressbooks/user/chris" and "/user/chris/addressbook" are the
same), out of band dataset class typing, and permitting "*" wild card
in place of a dataset path element.
5) Some people have indicated a desire for multi-valued attributes.
6) Do we need some sort of a "touch" operation?
7) Need to think more about the "subdataset" attribute and
inheritance.
8) Need to think more about the "o" ACL right and inheritance.
9) Need more examples.
1. Conventions Used in this Document
In examples, "C:" and "S:" indicate lines sent by the client and
server respectively. If such lines are wrapped without a new "C:" or
"S:" label, then the wrapping is for editorial clarity and is not
part of the command.
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The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY"
in this document are to be interpreted as described in RFC xxxx.
The protocol syntax specification uses the Augmented Backus-Naur Form
(ABNF) notation as specified in [IMAIL] with one exception; the
delimiter used with the "#" construct is a single space (SPACE) and
not one or more commas.
2. Protocol Overview
2.1. Link Level
The ACAP protocol assumes a reliable data stream such as provided by
TCP. When TCP is used, an ACAP server listens on port 674.
2.2. Commands and Responses
An ACAP session consists of the establishment of a client/server
connection, an initial greeting from the server, and client/server
interactions. These client/server interactions consist of a client
command, server data, and a server completion result.
All interactions transmitted by client and server are in the form of
lines; that is, strings that end with a CRLF. The protocol receiver
of an ACAP client or server is either reading a line, or is reading a
sequence of octets with a known count followed by a line. Both
clients and servers must be capable of handling lines of arbitrary
length.
2.2.1. Client Protocol Sender and Server Protocol Receiver
The client command begins an operation. Each client command is
prefixed with a identifier (typically a short alphanumeric string,
e.g., A0001, A0002, etc.) called a "tag". A different tag is
generated by the client for each command.
There are two cases in which a line from the client does not
represent a complete command. In one case, a command argument is
quoted with an octet count (see the description of literal in section
<section>); in the other case, the command arguments require server
feedback (see the AUTHENTICATE command). In some of these cases, the
server sends a command continuation request if it is ready for the
next part of the command. This response is prefixed with the token
"+".
Note: If, instead, the server detected an error in the
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command, it sends a BAD completion response with tag
matching the command (as described below) to reject the
command and prevent the client from sending any more of the
command.
It is also possible for the server to send a completion or
intermediate response for some other command (if multiple
commands are in progress), or untagged data. In either
case, the command continuation request is still pending;
the client takes the appropriate action for the response,
and reads another response from the server.
The ACAP server reads a command line from the client, parses the
command and its arguments, and transmits server data and a server
command completion result.
2.2.2. Server Protocol Sender and Client Protocol Receiver
Data transmitted by the server to the client come in four forms:
command continuation requests, command completion results,
intermediate responses, and untagged responses.
A command continuation request is prefixed with the token "+".
A command completion result indicates the success or failure of the
operation. It is tagged with the same tag as the client command
which began the operation. Thus, if more than one command is in
progress, the tag in a server completion response identifies the
command to which the response applies. There are three possible
server completion responses: OK (indicating success), NO (indicating
failure), or BAD (indicating protocol error such as unrecognized
command or command syntax error).
An intermediate response returns data which can only be interpreted
within the context of a command in progress. It is tagged with the
same tag as the client command which began the operation. Thus, if
more than one command is in progress, the tag in an intermediate
response identifies the command to which the response applies. A
tagged response other than "OK", "NO", or "BAD" is an intermediate
response.
An untagged response returns data or status messages which may be
interpreted outside the context of a command in progress. It is
prefixed with the token "*". Untagged data may be sent as a result
of a client command, or may be sent unilaterally by the server.
There is no syntactic difference between untagged data that resulted
from a specific command and untagged data that were sent
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unilaterally.
The protocol receiver of an ACAP client reads a response line from
the server. It then takes action on the response based upon the
first token of the response, which may be a tag, a "*", or a "+" as
described above.
A client MUST be prepared to accept any server response at all times.
This includes untagged data that it may not have requested.
This topic is discussed in greater detail in the Server Responses
section.
2.3. State and Flow Diagram
An ACAP server is in one of three states. Most commands are valid in
only certain states. It is a protocol error for the client to
attempt a command while the server is in an inappropriate state for
that command. In this case, a server will respond with a BAD command
completion result.
2.3.1. Non-Authenticated State
In non-authenticated state, the user must supply authentication
credentials before most commands will be permitted. This state is
entered when a connection starts.
2.3.2. Authenticated State
In authenticated state, the user is authenticated and most commands
will be permitted. This state is entered when acceptable
authentication credentials have been provided.
2.3.3. Logout State
In logout state, the session is being terminated, and the server will
close the connection. This state can be entered as a result of a
client request or by unilateral server decision.
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+--------------------------------------+
|initial connection and server greeting|
+--------------------------------------+
|| (1) || (2)
VV ||
+-----------------+ ||
|non-authenticated| ||
+-----------------+ ||
|| (4) || (3) ||
|| VV ||
|| +----------------+ ||
|| | authenticated | ||
|| +----------------+ ||
|| || (4) ||
VV VV VV
+--------------------------------------+
| logout and close connection |
+--------------------------------------+
(1) connection (ACAP greeting)
(2) rejected connection (BYE greeting)
(3) successful AUTHENTICATE command
(4) LOGOUT command, server shutdown, or connection closed
2.4. Operational Considerations
2.4.1. Untagged Status Updates
At any time, a server can send data that the client did not request.
2.4.2. Response when No Command in Progress
Server implementations are permitted to send an untagged response
while there is no command in progress. Server implementations that
send such responses MUST deal with flow control considerations.
Specifically, they must either (1) verify that the size of the data
does not exceed the underlying transport's available window size, or
(2) use non-blocking writes.
2.4.3. Autologout Timer
If a server has an inactivity autologout timer, that timer MUST be of
at least 30 minutes' duration. The receipt of ANY command from the
client during that interval MUST suffice to reset the autologout
timer.
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2.4.4. Multiple Commands in Progress
The client is not required to wait for the completion result of a
command before sending another command, subject to flow control
constraints on the underlying data stream. Similarly, a server is
not required to process a command to completion before beginning
processing of the next command, unless an ambiguity would result
because of a command that would affect the results of other commands.
If there is such an ambiguity, the server executes commands to
completion in the order given by the client.
2.5. Datasets and Entries
The primary data structure in ACAP is the "dataset", which is a named
set of entries. Datasets are named hierarchically, with each
component of the name preceded by a slash ("/") and containing one or
more UTF-8 characters (other than slash).
Each entry in a dataset is a set of attribute/value pairs. Each
attribute is a hierarchical name in UTF-8, with each component of the
name being separated with a period ("."). Each attribute/value pair
may have additional metadata; this is described in section <section>.
There must be exactly one "entry" attribute, whose value is unique
amongst all entries in the dataset and contains zero or more UTF-8
characters other than slash ("/") or dot (".").
Entries in a dataset are ordered in a server-determined manner.
The value of an attribute is a string containing one or more octets.
The semantics of a value are defined by the specification of its
attribute. Values of attributes ending in ".bin" contain arbitrary
data. Values of other attributes are textual and are restricted to
non-zero UTF-8 characters.
Attribute names are not permitted to contain "*", and entry names are
not permitted to begin with ".". Servers MUST return a BAD
completion result to clients which violate this.
2.6. Predefined Attributes
Attribute names which do not contain a dot (".") are reserved for
standardized attributes which have meaning in any dataset. The
following attributes are defined by the ACAP protocol.
entry Contains the name of the entry.
modtime
Contains the date and time, in UTC, any value or acl in the
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entry was last modified. This value is automatically updated
by the server and may not be directly modified by the client.
The value consists of 14 or more US-ASCII digits. The first
four indicate the year, the next two indicate the month, the
next two indicate the day of month, the next two indicate the
hour (0 - 23), the next two indicate the minute, and the next
two indicate the second. Any further digits indicate
fractions of a second.
The time, particularly fractions of a second, need not be
accurate. It is required, however, that any two entries in a
dataset changed by successive modifications have strictly
ascending modtime values.
subdataset
If this attribute is set, it indicates the existence of a
sub-dataset of this entry.
The value consists of a list of CRLF separated relative ACAP
URLs (see section <section> for ACAP URL specification) which
may be used to locate where the sub-dataset is actually
stored. The base URL for the subdataset attribute is formed
by appending the entry name followed by a "/" to the end of
the parent dataset name.
For example, if the dataset "/mailboxes/common" has an entry
"public-folder" with a subdataset attribute of ".", then there
exists a dataset "/mailboxes/common/public-folder". If the
value of the subdataset attribute was instead
"//other.acap.domain//mailboxes/common/public-folder" that
would indicate the dataset is actually located on a different
ACAP server.
A dataset is created by storing a "subdataset" attribute
including ".", and a sub-hierarchy of datasets is deleted by
clearing the value of the "subdataset" attribute on the entry
in the upper dataset.
2.7. Attribute metadata
Each attribute/value pair may have additional metadata associated
with it. For completeness, the attribute and value themselves are
defined as metadata. The defined items of metadata associated with
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an attribute/value pair are:
attribute
The attribute name. Read-only.
value The value.
value<ORIGIN.SIZE>
A substring of the value. ORIGIN is specified as a non-
negative decimal number indicating the octet position of the
first desired octet. An ORIGIN of 0 specifies the first octet
of the value. SIZE is specified as a positive, decimal
number, specifying the maximum number of octets desired. A
SIZE of 0 fetches all octets after the ORiGIN. Read-only.
size The length of the value, in octets. Read-only.
acl The access control list for the attribute/value pair, if one
exists. If the attribute/value pair does not have an ACL, NIL
is returned. Read-write. See section <section> for the
contents of an ACL.
myrights
The set of rights that the client has to the attribute/value
pair. Read-only. See section <section> for the possible
rights.
Additional items of metadata may be defined in extensions to this
protocol. Servers must respond to queries of unrecognized metadata
by returning a BAD command completion result.
2.8. Operational Command Overview
The AUTHENTICATE, NOOP, and LOGOUT commands provide basic protocol
services. The SEARCH command is used to select, sort, fetch and
monitor changes to attribute values and metadata. The UPDATECONTEXT
and FREECONTEXT commands are also used to assist in monitoring
changes in attribute values and metadata. The STORE command is used
to add, modify and delete entries and attributes. The DELETEDSINCE
command is used to assist a client in resynchronizing a cache with
the server. The SETQUOTA, GETQUOTA, SETACL, DELETEACL and MYRIGHTS
commands are used to examine or modifty quota usages and access
permissions.
3. Protocol Elements
This section defines data formats and other protocol elements used
throughout the ACAP protocol.
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3.1. Data Formats
ACAP uses textual commands and responses. Data in ACAP can be in one
of four forms: atom, number, string, parenthesized list, or NIL.
3.1.1. Atom
An atom consists of one to 1024 non-special characters.
3.1.2. Number
A number consists of one or more digit characters, and represents a
numeric value.
3.1.3. String
A string is in one of two forms: literal and quoted string. The
literal form is the general form of string. The quoted string form
is an alternative that avoids the overhead of processing a literal at
the cost of restrictions of what may be in a quoted string.
A literal is a sequence of zero or more octets (including CR and LF),
prefix-quoted with an octet count in the form of an open brace ("{"),
the number of octets, close brace ("}"), and CRLF. In the case of
literals transmitted from server to client, the CRLF is immediately
followed by the octet data.
There are two forms of literals transmitted from client to server.
The form where the open brace ("{") and number of octets is
immediately followed by a close brace ("}") and CRLF is called a
synchronizing literal. When sending a synchronizing literal, the
client must wait to receive a command continuation request (described
later in this document) before sending the octet data (and the
remainder of the command). The other form of literal, the non-
synchronizing literal, is used to transmit a string from client to
server without waiting for a command continuation request. The non-
synchronizing literal differs from the synchronizing literal by
having a plus ("+") between the number of octets and the close brace
("}") and by having the octet data immediately following the CRLF.
A quoted string is a sequence of zero to 1024 octets excluding CR,
LF, double quote (<">), or backslash ("\") with double quote (<">)
characters at each end.
The empty string is respresented as "" (a quoted string with zero
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characters between double quotes), as {0} followed by CRLF (a
synchronizing literal with an octet count of 0), or as {0+} followed
by a CRLF (a non-synchronizing literal with an octet count of 0).
Note: Even if the octet count is 0, a client transmitting a
synchronizing literal must wait to receive a command
continuation request.
3.1.3.1. 8-bit and Binary Strings
ACAP implementations MAY transmit 8-bit octets in literals. Except
in the values of attributes whose names end with ".bin", these octets
are interpreted as UTF-8 character sequences [UTF-8]. NUL octets are
only permitted in the values of attributes whose names end with
".bin". Servers SHOULD verify that any non-binary string sent by the
client has valid UTF-8 syntax before storing it.
3.1.4. Parenthesized List
Data structures are represented as a "parenthesized list"; a sequence
of data items, delimited by space, and bounded at each end by
parentheses. A parenthesized list can contain other parenthesized
lists, using multiple levels of parentheses to indicate nesting.
The empty list is represented as () -- a parenthesized list with no
members.
3.1.5 NIL
The special atom "NIL" represents the non-existence of a particular
data item that is represented as a string or parenthesized list, as
distinct from the empty string "" or the empty parenthesized list ().
3.2. ACAP URL scheme
ACAP URLs are used within the ACAP protocol for the "subdataset"
attribute, referrals and inheritance. They provide a convenient
syntax for referring to other ACAP datasets. The ACAP URL follows
the common Internet scheme syntax as defined in [BASIC-URL]. If
:<port> is omitted, the port defaults to 674.
An ACAP URL has the following general form:
url-acap ::= "acap://" url-server "/" url-enc-entry [url-filter]
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The <url-server> element (defined below) includes the hostname, and
optional user name, authentication mechanism and port number. The
<url-enc-entry> element contains the name of an entry path encoded
according to the rules in [BASIC-URL].
The <url-filter> element is made up of up to three components. The
first is a <url-attr-list> which specifies a list of interesting
attributes. The second is <url-depth> which specifies the DEPTH of
the search. The final element is <url-enc-search> which is an
encoded version of search-criteria. The default values for these
fields are "*", "DEPTH=1", and "ALL" respectively.
Note that unsafe or reserved characters such as " " or "?" must be
encoded according to the rules defined in [BASIC-URL]. Note that
octets encoded in the %A0 format with the high bit set are
interpreted according to UTF-8 [UTF8].
3.2.1. ACAP URL User Name and Authentication Mechanism
A user name and/or authentication mechanism may be supplied. They
are used in the "AUTHENTICATE" command after making the connection to
the ACAP server. If no user name or authentication mechanism is
supplied, then the user name "anonymous" is used with the SASL XXX
mechanism and the password is supplied as the Internet e-mail address
of the end user accessing the resource. If the URL supplies just a
user name, the program interpreting the ACAP URL SHOULD request a
password from the user if necessary.
An authentication mechanism can be expressed by adding
";AUTH=<enc_auth_type>" to the end of the user name. When such an
<enc_auth_type> is indicated, the client SHOULD request appropriate
credentials from that mechanism and use the "AUTHENTICATE" command.
If no user name is specified, one SHOULD be obtained from the
mechanism or requested from the user as appropriate.
The string ";AUTH=*" indicates that the client SHOULD select an
appropriate authentication mechanism. It MAY use any mechanism
listed in the initial ACAP response. If no user name is specified
and no appropriate authentication mechanisms are available, the
client SHOULD fall back to anonymous login as described above. This
allows a URL which grants read-write access to authorized users, and
read-only anonymous access to other users.
Note that if unsafe or reserved characters such as " " or ";" are
present in the user name or authentication mechanism, they MUST be
encoded as described in BASE-URL [BASE-URL].
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3.2.2. Relative ACAP URLs
Because ACAP uses "/" as the hierarchy separator for dataset paths,
it works well with the relative URL rules defined in REL-URL [REL-
URL].
The <aauth> grammar element is considered part of the user name for
purposes of resolving relative ACAP URLs.
The base URL for a relative URL stored in an attribute's value is
formed by taking the path to the dataset containing that attribute,
appending a "/" followed by the entry name of the entry containing
that attribute followed by "/".
3.3. Contexts
A context is an ordered subset of entries in a dataset, created by a
SEARCH command with a MAKECONTEXT modifier. Context names are
client-generated strings and must not start with the slash ('/')
character.
Contexts only have scope within the ACAP session in which they were
created. There is a server-imposed limit on the number of contexts
that may exist at one time within a session. The minimum value for
this limit is 100, if the server supports a larger limit it must
advertise it in a CONTEXTLIMIT capability.
3.4. Orderings
An ordering is a named collation function which takes two input
strings and determines whether they are greater than, less than, or
equal to each other. Orderings are used both for simple equality
searching, for ordinal comparision searching and for sorting of
attributes. An ordering is prefixed by either "+" or "-". If
prefixed by "-", then the order is reversed. In all collation
functions, NIL is always less than any other value and is equal only
to itself.
Additional ordering functions may be registered with IANA according
to the rules in section <section>.
The following ordering functions are defined by this standard:
octet The octet ordering function interprets the value of an
attribute as a series of unsigned octets with ordinal values
from 0 to 255. Each octet pair is compared in sequence
until the octets are unequal or the end of the string is
reached. When collating two strings where the shorter is a
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prefix of the longer, the shorter string is interpreted as
having a smaller ordinal value. The +octet form collates
smaller ordinal values earlier, and the -octet form collates
larger ordinal values earlier. For non-binary values, the
+octet ordering is equivalent to the ANSI C strcmp()
function applied to C string representations of the values.
en-nocase
The en-nocase ordering function first applies a mapping to
the attribute values which translates all US-ASCII letters
to uppercase (octet values 0x61 to 0x7A are translated to
octet values 0x41 to 0x5A respectively), then applies the
octet ordering function as described above. With this
function the values "hello" and "HELLO" have the same
ordinal value and are considered equal.
numeric
The numeric ordering function assigns ordinal values based
on a US-ASCII encoded decimal positive integer
interpretation. With the numeric function, all values which
do not begin with a digit are considered equal with an
ordinal value of -1. Otherwise, all US-ASCII digits (octet
values 0x30 to 0x39) are interpreted starting from the
beginning of the string to the first non-digit or the end of
the string.
3.5. Server Status Responses
An OK, NO or BAD response from the server, whether tagged or
untagged, is considered a status response. Status responses may
include an optional response code. A response code consists of data
inside parentheses in the form of an atom, possibly followed by a
space and arguments. The response code contains additional
information or status codes for client software beyond the OK/NO/BAD
condition, and are defined when there is a specific action that a
client can take based upon the additional information.
The currently defined response codes are:
ALERT The human-readable text contains a special alert
that MUST be presented to the user in a fashion
that calls the user's attention to the message.
MODIFIED This response code indicates that a conditional
store failed because the MODTIME on the entry is
later than the modtime specified with the STORE
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command.
PERMISSION A STORE, SETQUOTA, or SETACL command failed due to
insufficient permission.
QUOTA A STORE command which would have increased the size
of the dataset failed due to insufficient quota.
REFER This response code may be returned in a tagged NO
response to any command that takes a dataset name
as a parameter. It has one argument with the
syntax of a relative URL. It is a referral,
indicating that the command should be retried using
the dataset named in the relative URL.
TOOMANY This response code may be returned in a tagged OK
response to a SEARCH command which includes the
LIMIT modifier. The argument returns the number of
matching entries.
TRYFREECONTEXT This response code may be returned in a tagged NO
respose to a SEARCH command which includes the
MAKECONTEXT modifier. It indicates that a new
context may not be created due to the server's
limit on the number of existing contexts.
WAYTOOMANY This response code may be returned in a tagged OK
response to a SEARCH command which includes a
HARDLIMIT search modifier. It indicates that the
SEARCH would have returned more entries than the
hardlimit permitted.
Additional response codes defined by particular client or server
implementations should be prefixed with an "X" until they are
added to a revision of this protocol. Client implementations MUST
ignore response codes that they do not recognize.
3.6. Server Command Continuation Request
The command continuation request is indicated by a "+" token instead
of a tag. This indicates that the server is ready to accept the
continuation of a command from the client. The remainder of this
response is a line of text.
This response is used in the AUTHENTICATE command to transmit server
data to the client, and request additional client data. This
response is also used if an argument to any command is a
synchronizing literal.
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The client is not permitted to send the octets of a synchronizing
literal unless the server indicates that it expects it. This permits
the server to process commands and reject errors on a line-by-line
basis, assuming it checks for non-synchronizing literals at the end
of each line. The remainder of the command, including the CRLF that
terminates a command, follows the octets of the literal. If there
are any additional command arguments the literal octets are followed
by a space and those arguments.
Example: C: A099 FREECONTEXT {10}
S: + "Ready for additional command text"
C: FRED
C: FOOB
S: A099 OK "FREECONTEXT completed"
C: A044 BLURDYBLOOP {102856}
S: A044 BAD "No such command as 'BLURDYBLOOP'"
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4. Protocol Specification
ACAP commands and responses are described in this section. Commands
are organized first by the state in which the command is permitted,
then by a general category of command type.
Command arguments, identified by "Arguments:" in the command
descriptions below, are described by function, not by syntax. The
precise syntax of command arguments is described in the Formal Syntax
section.
Some commands cause specific server data to be returned; these are
identified by "Data:" in the command descriptions below. See the
response descriptions in the Responses section for information on
these responses, and the Formal Syntax section for the precise syntax
of these responses. It is possible for server data to be transmitted
as a result of any command; thus, commands that do not specifically
require server data specify "no specific data for this command"
instead of "none".
The "Result:" in the command description refers to the possible
tagged status responses to a command, and any special interpretation
of these status responses.
4.1. Initial Connection
Upon session startup, the server sends one of two untagged responses:
ACAP or BYE. The untagged BYE response is described in section
<section>.
4.1.1. ACAP Untagged Response
Data: capability list
The untagged ACAP response indicates the session is ready to
accept commands and contains a space-separated listing of
capabilities that the server supports. Each capability is an atom
name, possibly followed by a string argument in parenthesis.
ACAP capability names MUST be defined in a standards track or IESG
approved experimental RFC and registered with IANA according to
the rules in section <section>.
Client implementations SHOULD NOT require any capability name, and
MUST ignore any unknown capability names.
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The following initial capabilities are defined:
CONTEXTLIMIT
The CONTEXTLIMIT capability has one argument which is a
number describing the maximum number of contexts the server
supports per connection. The number 0 indicates the server
has no limit, otherwise this number MUST be greater than
100.
IMPLEMENTATION
The IMPLEMENTATION capability has one argument which is a
string describing the server implementation. ACAP clients
MUST NOT alter their behavior based on this value. It is
intended primarily for debugging purposes.
ORDERINGS
The ORDERINGS capability includes a list of the
ordering/comparison functions which the server supports.
See section <section> for a description of
ordering/comparison functions.
SASL The SASL capability includes a list of the authentication
mechanisms supported by the server. See [SASL] for more
information.
Example: S: * OK IMPLEMENTATION("ACME v3.5") SASL("CRAM-MD5"
"GSSAPI")
4.2. Any State
The following commands and responses are valid in any state.
4.2.1. NOOP Command
Arguments: none
Data: no specific data for this command (but see below)
Result: OK - noop completed
BAD - command unknown or arguments invalid
The NOOP command always succeeds. It does nothing. It can be
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used to reset any inactivity autologout timer on the server.
Example: C: a002 NOOP
S: a002 OK "NOOP completed"
4.2.2. LOGOUT Command
Arguments: none
Data: mandatory untagged response: BYE
Result: OK - logout completed
BAD - command unknown or arguments invalid
The LOGOUT command informs the server that the client is done with
the session. The server must send a BYE untagged response before
the (tagged) OK response, and then close the network connection.
Example: C: A023 LOGOUT
S: * BYE "ACAP Server logging out"
S: A023 OK "LOGOUT completed"
(Server and client then close the connection)
4.2.3. OK Response
Data: optional response code
human-readable text
The OK response indicates an information message from the server.
When tagged, it indicates successful completion of the associated
command. The human-readable text may be presented to the user as
an information message. The untagged form indicates an
information-only message; the nature of the information may be
indicated by a response code.
Example: S: * OK (ALERT) "System shutdown in 10 minutes"
4.2.4. NO Response
Data: optional response code
human-readable text
The NO response indicates an operational error message from the
server. When tagged, it indicates unsuccessful completion of the
associated command. The untagged form indicates a warning; the
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command may still complete successfully. The human-readable text
describes the condition.
Example: C: A001 NOOP
S: * NO (ALERT) "Dataset '/addressbook/user/fred' is at
98% of quota"
S: A001 OK "NOOP"
...
C: A222 STORE ("/mailboxes/comp.mail.misc"
"mailbox.creation-time"
"19951206103412")
S: A222 NO (PERMISSION) "Permission denied"
4.2.5. BAD Response
Data: optional response code
human-readable text
The BAD response indicates an error message from the server. When
tagged, it reports a protocol-level error in the client's command;
the tag indicates the command that caused the error. The untagged
form indicates a protocol-level error for which the associated
command can not be determined; it may also indicate an internal
server failure. The human-readable text describes the condition.
Example: C: ...empty line...
S: * BAD "Empty command line"
C: A443 BLURDYBLOOP
S: A443 BAD "Unknown command"
C: A444 NOOP Hello
S: A444 BAD "invalid arguments"
4.2.6. BYE Untagged Response
Data: optional response code
human-readable text
The untagged BYE response indicates that the server is about to
close the connection. The human-readable text may be displayed to
the user in a status report by the client. The BYE response may
be sent as part of a normal logout sequence, or as a panic
shutdown announcement by the server. It is also used by some
server implementations as an announcement of an inactivity
autologout.
This response is also used as one of two possible greetings at
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session startup. It indicates that the server is not willing to
accept a session from this client.
Example: S: * BYE "Autologout; idle for too long"
4.3. Non-Authenticated State
In non-authenticated state, the AUTHENTICATE command establishes
authentication and enters authenticated state. The AUTHENTICATE
command provides a general mechanism for a variety of authentication
techniques.
Server implementations may allow non-authenticated access to certain
information. The convention is to use an AUTHENTICATE command with
the userid "anonymous" with the SASL XXX mechanism.
Once authenticated (including as anonymous), it is not possible to
re-enter non-authenticated state.
In addition to the universal commands (NOOP and LOGOUT), the
following commands are valid in non-authenticated state:
AUTHENTICATE.
4.3.1. AUTHENTICATE Command
Arguments: SASL mechanism name
optional initial response
Data: continuation data may be requested
Result: OK - authenticate completed, now in authenticated state
NO - authenticate failure: unsupported authentication
mechanism, credentials rejected
BAD - command unknown or arguments invalid,
authentication exchange cancelled
The AUTHENTICATE command indicates an authentication mechanism to
the server. If the server supports the requested authentication
mechanism, it performs an authentication protocol exchange to
authenticate and identify the user. Optionally, it also
negotiates a security layer for subsequent protocol interactions.
If the requested authentication mechanism is not supported, the
server rejects the AUTHENTICATE command by sending a tagged NO
response.
The authentication protocol exchange consists of a series of
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server challenges and client answers that are specific to the
authentication mechanism. A server challenge consists of a
command continuation request with the "+" token followed by a
BASE64 encoded string. The client answer consists of a line
consisting of a BASE64 encoded string. If the client wishes to
cancel an authentication exchange, it should issue a line with a
single "*". If the server receives such an answer, it must reject
the AUTHENTICATE command by sending a tagged BAD response.
The optional initial-response argument to the AUTHENTICATE command
is used to save a round trip when using authentication mechanisms
that are defined to send no data in the initial challenge. When
the initial-response argument is used with such a mechanism, the
initial empty challenge is not sent to the client and the server
uses the data in the initial-response argument as if it were sent
in response to the empty challenge. If the initial-response
argument to the AUTHENTICATE command is used with a mechanism
that sends data in the initial challenge, the server rejects the
AUTHENTICATE command by sending a tagged NO response.
The service name specified by this protocol's profile of SASL is
"acap".
If a security layer is negotiated through the SASL authentication
exchange, it takes effect immediately following the CRLF that
concludes the authentication exchange for the client, and the CRLF
of the tagged OK response for the server.
The server is not required to support any particular
authentication mechanism, nor are authentication mechanisms
required to support any protection mechanisms. If an AUTHENTICATE
command fails with a NO response, the client may try another
authentication mechanism by issuing another AUTHENTICATE command.
In other words, the client may request authentication types in
decreasing order of preference.
Example: S: * OK IMPLEMENTATION("Blorfysoft v3.5")
SASL(KERBEROS_V4)
C: A001 AUTHENTICATE KERBEROS_V4
S: + AmFYig==
C: BAcAQU5EUkVXLkNNVS5FRFUAOCAsho84kLN3/IJmrMG+25a4DT
+nZImJjnTNHJUtxAA+o0KPKfHEcAFs9a3CL5Oebe/ydHJUwYFd
WwuQ1MWiy6IesKvjL5rL9WjXUb9MwT9bpObYLGOKi1Qh
S: + or//EoAADZI=
C: DiAF5A4gA+oOIALuBkAAmw==
S: A001 OK "Kerberos V4 authentication successful"
Note: the line breaks in the first client answer are for
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editorial clarity and are not in real authenticators.
4.4. Searching
This section describes the SEARCH command, for retrieving data from
datasets.
4.4.1. SEARCH Command
Arguments: dataset or context name
optional list of modifiers
search criteria
Data: intermediate responses: ENTRY, MODTIME, REFER
untagged responses: ADDTO, REMOVEFROM, CHANGE, MODTIME
Result: OK - search completed
NO - search failure: can't perform search
BAD - command unknown or arguments invalid
The SEARCH command identifies a subset of entries in a dataset and
returns information on that subset to the client.
The first argument to SEARCH identifies what is to be searched.
If the string begins with a slash ("/"), it is the name of a
dataset to be searched, otherwise it is a name of a context that
was created by a SEARCH command given previously in the session.
A successful SEARCH command MUST result in a MODTIME intermediate
response.
Following that are zero or more modifiers to the search. Each
modifier may be specified at most once. The defined modifiers
are:
DEPTH number The SEARCH command will traverse the dataset tree
up to the specified depth. ENTRY responses will
include the full path to the entry. A value of "0"
indicates that the search should traverse the
entire tree. A value of "1" is the default and
indicates only the specified dataset should be
searched. If a dataset is traversed which is not
located on the current server, then a REFER
intermediate response is returned for that subtree
and the search continues.
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If this is used in combination with a SORT or
MAKECONTEXT operator, the server MUST return a BAD
command completion result.
HARDLIMIT number
If the SEARCH command would result in more than
number entries, the SEARCH fails with a NO
completion result with a WAYTOOMANY response code.
LIMIT number number
Limits the number of intermediate ENTRY responses
that the search may generate. The first numeric
argument specifies the limit, the second number
specifies the number of entries to return if the
number of matches exceeds the limit. If the limit
is exceeded, the SEARCH command still succeeds,
returning the total number of matches in a TOOMANY
response code in the tagged OK response.
MAKECONTEXT context
The SEARCH command creates a context with the name
given in the argument to refer to the matching
entries.
If the SEARCH is successful, the context name may
then be given as an argument to subsequent SEARCH
commands to search the set of matching entries.
If a context with the specified name already
exists, it is first freed. If a new context may
not be created due to the server's limit on the
number of existing contexts, the command fails,
returning a TRYFREECONTEXT response code in the
tagged NO response.
Contexts are discussed in more detail in section
<section>.
NOTIFYCONTEXT Requests that the server send untagged ADDTO,
REMOVEFROM, CHANGE, and MODTIME responses while the
context created or referenced by this SEARCH
command exists. The server MAY issue untagged
ADDTO, REMOVEFROM, CHANGE and MODTIME notifications
for a context at any time between the issuing of
the SEARCH command with NOTIFYCONTEXT and the
completion of a FREECONTEXT command for the
context. After issuing a sequence of ADDTO,
REMOVEFROM or CHANGE notifications, the server MUST
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issue an untagged MODTIME notification indicating
that the client has all updates to the entries in
the context up to and including the given modtime
value.
The client MAY issue a subsequent SEARCH on the
context with a NOTIFYCONTEXT modifier, and this MAY
be used to change the list of attributes and
metadata included in ADDTO and CHANGE responses for
the context.
RETURN (metadata...)
Specifies what is to be returned in intermediate
ENTRY responses. If this modifier is not
specified, no intermediate ENTRY responses are
returned.
Inside the parentheses is a list of attributes,
each optionally followed by a parenthesized list of
metadata. If the parenthesized list of metadata is
not specified, it defaults to "(value)".
An attribute name with a trailing "*" requests all
attributes with that prefix. A "*" by itself
requests all attributes. If the parenthesized list
of metadata is not specified for an attribute with
a trailing "*", it defaults to "(attribute value)".
Following the last intermediate ENTRY response, the
server returns a single intermediate MODTIME
response.
SORT (attribute ordering...)
Specifies the order in which any resulting ENTRY
replies are to be returned to the client. The SORT
modifier takes as an argument a parenthesized list
of one or more attribute/ordering pairs. Attribute
lists the attribute to sort on, ordering specifies
the name of the collation rule to apply to the
values of the attribute. Successive
attribute/ordering pairs are used to order two
entries only when all preceeding pairs indicate the
two entries collate the same.
If the SORT modifier is used in conjunction with
the MAKECONTEXT modifier, the SORT modifier
specifies the ordering of entries in the created
context.
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If no SORT modifier is specified, or none of the
attribute/ordering pairs indicates an order for the
two entries, the server uses the order of the
entries that exists in the context or dataset being
searched.
Following the modifiers is the search criteria. Searching
criteria consist of one or more search keys. Search keys may be
combined using the AND, and OR search keys. For example, the
criteria (the newline is for readability and not part of the
criteria):
AND COMPARE modtime +octet "19951206103400"
COMPARE modtime -octet "19960112000000"
refers to all entries modified between 10:34 December 6 1995 and
midnight January 12, 1996 UTC.
The currently defined search keys are as follows.
ALL This matches all entries.
AND search-key1 search-key2
Entries that match both search keys.
COMPARE attribute ordering value
Entries for which the specified attribute collates using the
specified ordering the same or later than the specified
value.
COMPARESTRICT attribute ordering value
Entries for which the specified attribute collates using the
specified ordering later than the specified value.
EQUAL attribute ordering value
Entries for which the specified attribute collates using the
specified ordering the same as the specified value.
NOT search-key
Entries that do not match the specified search key.
OR search-key1 search-key2
Entries that match either search key.
RANGE start end time
Entries which are within the specified range of the context's
ordering. The lowest-ordered entry in the context is
assigned number one, the next lowest entry is assigned number
two, and so on. The numeric arguments specify the lowest and
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highest numbers to match. The time specifies that the client
has processed notifications for the context up to the
specified time. If the context has been modified since then,
the server MUST either return a NO with a MODIFIED response
code, or return the results that the SEARCH would have
returned if none of the changes since that time had been
made.
RANGE is only permitted on contexts. If RANGE is used with a
dataset, the server MUST return a BAD command completion
result.
Example: C: [TODO - write examples]
4.4.2. ENTRY Intermediate Response
Data: entry name
entry data
The ENTRY intermediate response occurs as a result of a SEARCH
command. This is the means by which dataset entries are returned
to the client. The entry with the given name matches the search.
Following the entry name is a set of zero or more strings, each
containing the respective metadata, contained in the entry, that
was specified in the RETURN search modifier.
4.4.3. MODTIME Intermediate Response
Data: modtime value
The MODTIME intermediate response occurs as a result of a SEARCH
command. It indicates that the just created context or the
previously returned ENTRY responses include all updates to the
returned entries up to and including the modtime value in the
argument.
4.4.4. REFER Intermediate Response
Data: dataset path
ACAP URL
The REFER intermediate response occurs as a result of a multi-
level SEARCH where one of the levels is located on a different
server. The reponse indicates the dataset which is not located on
the current server and an ACAP URL for where that dataset may be
found.
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4.5. Contexts
The following commands use contexts created by a SEARCH command with
a MAKECONTEXT modifier.
4.5.1. FREECONTEXT Command
Arguments: context name
Data: no specific data for this command
Result: OK - freecontext completed
NO - freecontext failure: no such context
BAD - command unknown or arguments invalid
The FREECONTEXT command causes the server to free all state
associated with the named context. The context may no longer be
searched and the server will no longer issue any untagged
responses for the context. The context is no longer counted
against the server's limit on the number of contexts.
Example: C: A683 FREECONTEXT "blurdybloop"
S: A683 OK "Freecontext completed"
4.5.2. UPDATECONTEXT Command
Arguments: list of context names
Data: untagged responses: ADDTO REMOVEFROM CHANGE MODTIME
Result: OK - Updatecontext completed: all updates completed
NO - Updatecontext failed: no such context
BAD - command unknown or arguments invalid
The UPDATECONTEXT command causes the server to ensure that the
client is notified of all changes to the contexts listed as
arguments up to the current time. The contexts listed in the
arguments must have been previously given to a successful SEARCH
command with a NOTIFYCONTEXT modifier. A MODTIME untagged
response MUST be returned if any read-write metadata in the
dataset changed since the last MODTIME on that context. This
includes metadata which is not listed in the RETURN modifier on
the last SEARCH command with a NOTIFYCONTEXT modifier for this
context.
While a server may issue untagged ADDTO, REMOVEFROM, CHANGE, and
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MODTIME at any time, the UPDATECONTEXT command is used to "prod"
the server to send any notifications it has not sent yet.
The UPDATECONTEXT command SHOULD NOT be used to poll for updates.
Example: C: Z4S9 UPDATECONTEXT "blurdybloop" "blarfl"
S: Z4S9 OK "client has been notified of all changes"
4.5.3. ADDTO Untagged Response
Data: context name
entry name
position
metadata list
The untagged ADDTO response informs the client that an entry has
been added to a context. The response includes the position
number of the added entry (the first entry in the context is
numbered 1) and those metadata contained in the entry which match
the RETURN statement specified in the last SEARCH command on the
context with a NOTIFYCONTEXT search modifier.
The ADDTO response implicitly adds one to the position of all
members of the context which had position numbers that were
greater than or equal to the ADDTO position number.
Example: S: * ADDTO "blurdybloop" "fred" 15 ("addressbook.email"
"fred@rock.org")
4.5.4. REMOVEFROM Untagged Response
Data: context name
entry name
old position
The untagged REMOVEFROM response informs the client that an entry
has been removed from a context. The response includes the
position number that the removed entry used to have (the first
entry in the context is numbered 1).
The REMOVEFROM response implicity subtracts one from the position
numbers of all members of the context which had position numbers
greater than the REMOVEFROM position number.
Example: S: * REMOVEFROM "blurdybloop" "fred" 15
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4.5.5. CHANGE Untagged Response
Data: context name
entry name
old position
new position
metadata list
The untagged CHANGE response informs the client that an entry in a
context has either changed position in the context or has changed
the values of one or more of the attributes specified in the last
SEARCH command with a NOTIFYCONTEXT search modifier for the
context.
The response includes the previous and current position numbers of
the entry (the first entry in the context is numbered 1) and those
attribute/value pairs contained in the entry which match
attributes specified in the last SEARCH command with a
NOTIFYCONTEXT search modifier for the context.
The CHANGE reponse implicitly changes the position numbers of all
entries which had position numbers between the old and new
position. If old position is less than new position, than one is
subtracted from all entries which had position numbers in that
range. Otherwise one is added to all entries which had position
numbers in that range. If the old position and new position are
the same, then no implicit position renumbering occurs.
Example: S: * CHANGE "blurdybloop" "fred" 15 10
("addressbook.email" "fred@stone.org")
4.5.6. MODTIME Untagged Response
Data: context name
modtime value
The untagged MODTIME response informs the client that it has
recieved all updates to entries in the context which have modtime
values less than or equal to the modtime value in the argument.
Example: S: * MODTIME mycontext "19970320162338"
4.6. Dataset modification
The following commands and responses handle modification of datasets.
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4.6.1. STORE Command
Arguments: entry store list
Data: no specific data for this command
Result: OK - store completed
NO - store failure: can't store that name
UNCHANGEDSINCE specified and entry changed
BAD - command unknown or arguments invalid
invalid UTF-8 syntax
Creates, modifies or deletes the named entries in the named
datasets. The values of metadata not specified in the command are
not changed. Setting the "value" metadata of an attribute to NIL
removes that attribute from the entry. Setting the "value"
metadata of the "entry" attribute to NIL removes that entry from
the dataset. Changing the value of the "entry" attribute
indicates a request to rename the entry.
For each entry listed, an "UNCHANGEDSINCE" time may be included.
If the "modtime" of the entry is later than the unchangedsince
time, then the store fails with a MODIFIED response code. Clients
writing to a shared dataset SHOULD use UNCHANGEDSINCE when
modifying an existing entry.
The server MUST either make all the changes specified or make none
of them. If the STORE command includes no metadata for an entry,
that entry's MODTIME MUST NOT be updated.
The reserved attribute "modtime" may not be included in the
metadata list, but will automatically be updated.
Example: C: A342 STORE ("/addressbook/user/fred/ABC547"
"addressbook.phone" "555-1234"
"addressbook.Common Name"
"Barney Rubble" "addressbook.email" NIL)
S: A342 OK "Store completed"
C: A343 STORE ("/addressbook/group/Tech/ABD42"
UNCHANGEDSINCE "19970320162338"
"addressbook.prs.hair-length" "10 inches")
S: A343 NO (MODIFIED) "'ABD42' has been changed by
somebody else."
C: A344 STORE ("/addressbook/group/Tech/ACD54" "entry"
NIL)
S: A344 OK "Store completed"
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4.6.2. DELETEDSINCE Command
Arguments: dataset name
time
Data: intermediate response: DELETED
Result: OK - DELETED completed
NO - DELETED failure: can't read dataset
date too far in the past
BAD - command unknown or arguments invalid
The DELETEDSINCE command returns in intermediate DELETED replies
the names of entries that have been deleted from the named dataset
since the given time.
Servers may impose a limit on the number or age of deleted entry
names they keep track of. If the server does not have information
going back to the specified time, the command fails, returning a
TOOOLD response code in the tagged NO response.
Example: C: Z4S9 DELETEDSINCE "/mailboxes/common" 19951205103412
S: Z4S9 DELETED "blurdybloop"
S: Z4S9 DELETED "anteaters"
S: Z4S9 OK "DELETEDSINCE completed"
C: Z4U3 DELETEDSINCE "/mailboxes/common" 19951009040854
S: Z4U3 NO (TOOOLD) "Don't have that information"
4.6.3. DELETED Intermediate Response
Data: entry name
The untagged DELETED response occurs as a result of a DELETEDSINCE
command. It returns an entry that has been deleted from the
dataset specified in the DELETEDSINCE command.
Example: S: Z4S9 DELETED "blurdybloop"
4.7. Access Control Lists
An access control list is a tab-separated set of identifier,rights
pairs.
Identifier is a UTF-8 string. The identifier anyone is reserved to
refer to the universal identity (all authentications, including
anonymous). All user name strings accepted by the AUTHENTICATE
command to authenticate to the ACAP server are reserved as
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identifiers for the corresponding user. Identifiers starting with a
dash ("-") are reserved for "negative rights", described below. All
other identifier strings have implementation-defined semantics.
Rights is a string listing a (possibly empty) set of alphanumeric
characters, each character listing a set of operations which is being
controlled. Letters are reserved for ``standard'' rights, listed
below. The set of standard rights may only be extended by a
standards-track or IESG approved experimental RFC. Digits are
reserved for implementation or site defined rights. The currently
defined standard rights are:
r - read
w - write
i - insert (store a new value)
o - override (see section <section>)
a - administer (perform store on ACL attribute/metadata)
An implementation may force rights to always or never be granted.
Rights are never tied, unlike the IMAP ACL extension [IMAP-ACL].
It is possible for multiple identifiers in an access control list to
apply to a given user (or other authentication identity). For
example, an ACL may include rights to be granted to the identifier
matching the user, one or more implementation-defined identifiers
matching groups which include the user, and/or the identifier
"anyone". How these rights are combined to determine the user's
access is implementation-defined. An implementation may choose, for
example, to use the union of the rights granted to the applicable
identifiers. An implementation may instead choose, for example, to
only use those rights granted to the most specific identifier present
in the ACL. A client may determine the set of rights granted to the
logged-in user for a given mailbox by using the MYRIGHTS command.
When an identifier in an ACL starts with a dash ("-"), that indicates
that associated rights are to be removed from the identifier that is
prefixed by the dash. For example, if the identifier "-fred" is
granted the "w" right, that indicates that the "w" right is to be
removed from users matching the identifier "fred". Implementations
need not support having identifiers which start with a dash in ACLs.
Each attribute of each entry of a dataset may potentially have an
ACL. If an attribute in an entry does not have an ACL, then access
is controlled by a default ACL for that attribute in the dataset, if
it exists. If there is no default ACL for that attribute in the
dataset, access is controlled by a default ACL for that dataset. The
default ACL for a dataset must exist.
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In order to perform any manipulation on an entry in a dataset, the
client must have 'r' rights on the "entry" attribute of the entry.
Implementations should take care not to reveal via error messages the
existence of an entry for which the client does not have 'r' rights.
A client does not need access to the "subdataset" attribute of the
parent dataset in order to access the contents of a dataset.
Many of the ACL commands and responses include an ``acl object''
parameter, for specifying what the ACL applies to. This is a
parenthesized list. The list contains just the dataset name when
referring to the default ACL for a dataset. The list contains a
dataset name and an attribute name when referring to the default ACL
for an attribute in a dataset. The list contains a dataset name, an
attribute name, and an entry name when referring to the ACL for an
attribute of an entry of a dataset.
4.7.1. SETACL Command
Arguments: acl object
authentication identifier
access rights
Data: no specific data for this command
Result: OK - setacl completed
NO - setacl failure: can't set acl
BAD - command unknown or arguments invalid
The SETACL command changes the access control list on the
specified object so that the specified identifier is granted the
permissions enumerated in rights. If the object did not
previously have an access control list, one is created.
Example: C: A123 SETACL ("/addressbook/user/joe/public") anyone r
S: A123 OK "Setacl complete"
C: A124 SETACL ("/mailboxes/common") B1FF rwa
S: A124 NO (PERMISSION) "'B1FF' not permitted to modify
access rights
for '/mailboxes/common'"
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4.7.2. DELETEACL Command
Arguments: acl object
optional authentication identifier
Data: no specific data for this command
Result: OK - deleteacl completed
NO - deleteacl failure: can't delete acl
BAD - command unknown or arguments invalid
If given the optional identifier argument, the DELETEACL command
removes any portion of the access control list on the specified
object for the specified identifier.
If not given the optional identifier argument, the DELETEACL
command removes the ACL from the object entirely, causing access
to be controlled by a higher-level default ACL. This form of the
DELETEACL command is not permitted on the default ACL for a
dataset and servers MUST return a BAD.
Example: C: A223 DELETEACL ("/addressbook/user/joe/public") anyone
S: A223 OK "Deleteacl complete"
C: A224 DELETEACL ("/mailboxes/common")
S: A224 BAD "Can't delete ACL from dataset"
C: A225 DELETEACL ("/addressbook/user/fred"
"addressbook.email" "barney")
S: A225 OK "Deleteacl complete"
4.7.3. MYRIGHTS Command
Arguments: acl object
Data: intermediate responses: MYRIGHTS
Result: OK - myrights completed
NO - myrights failure: can't get rights
BAD - command unknown or arguments invalid
The MYRIGHTS command returns the set of rights that the client has
to the given dataset or dataset attribute.
Example: C: A003 MYRIGHTS ("/mailboxes/common")
S: A003 MYRIGHTS "r"
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S: A003 OK "Myrights complete"
4.7.4. MYRIGHTS Intermediate Response
Data: rights
The MYRIGHTS response occurs as a result of a MYRIGHTS command.
The argument is the set of rights that the client has for the
object referred to in the MYRIGHTS command.
4.7.5. LISTRIGHTS Command
Arguments: acl object
authentication identifier
Data: untagged responses: LISTRIGHTS
Result: OK - listrights completed
NO - listrights failure: can't get rights list
BAD - command unknown or arguments invalid
The LISTRIGHTS command takes an object and an identifier and
returns information about what rights may be granted to the
identifier in the ACL for the object.
Example: C: a001 LISTRIGHTS ("/mailboxes") smith
S: a001 LISTRIGHTS ("/mailboxes") smith r w
S: a001 OK Listrights completed
C: a005 LISTRIGHTS ("/mailboxes" archive.imap) anyone
S: a005 LISTRIGHTS ("/mailboxes" archive.imap) anyone ""
r w
S: a005 OK Listrights completed
4.7.6. LISTRIGHTS Intermediate Response
Data: acl object
identifier
required rights
list of optional rights
The LISTRIGHTS response occurs as a result of a LISTRIGHTS
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command. The first two arguments are the object and identifier
for which this rights list applies. Following the identifier is a
string containing the (possibly empty) set of rights the
identifier will always be granted on the dataset or attribute.
Following this are zero or more strings each containing a single
right the identifier may be granted in the dataset or attribute.
The same right may not be listed more than once in the LISTRIGHTS
response.
4.8. Quotas
Quotas are used to manage storage consumed by ACAP datasets. A quota
root is a place where a resource limit may be set which applies to an
implementation dependant subset of datasets.
4.8.1. SETQUOTA Command
Arguments: quota root
resource limit in octets or NIL
Data: intermediate responses: QUOTA
Result: OK - Quota root resource limit modified
NO - Quota failure: can't modify resourse limit
BAD - command unknown or arguments invalid
The SETQUOTA command takes the name of a quota root and a number
indicating the desired resource limit in octets on all datasets
within that root. A value of "0" indicates no resource limit is
desired. A value of NIL indicates the quota root should be
removed.
If the named quota root did not previously exist and a value other
than NIL is specified, an implementation SHOULD create it. If the
quota root exists and a value of NIL is specified, an
implementation SHOULD delete the quota root. In either case the
implementation may change the quota root which applies to any
number of datasets.
Example: C: A042 SETQUOTA "/user/fred" 1048576
S: A042 QUOTA "/user/fred" 1048576 0
S: A042 OK "Setquota completed"
C: A043 SETQUOTA "/usr/fred" NIL
S: A043 OK "Setquota completed"
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4.8.2. GETQUOTA Command
Arguments: dataset
Data: intermediate responses: QUOTA
Result: OK - Quota information returned
NO - Quota failure: can't access resourse limit
BAD - command unknown or arguments invalid
The GETQUOTA command takes the name of a dataset, and returns in
an intermediate QUOTA response the name of the quota root, the
amount of the resource limit on that root and the amount of that
resource limit which is used.
Example: C: A043 GETQUOTA "/option/user/fred/common"
S: A043 QUOTA "/user/fred" 1024 50
S: A043 OK "Getquota completed"
4.8.3. QUOTA Intermediate Response
Data: quota root
resource limit in octets
amount of resource limit used
The QUOTA intermediate response is generated as a result of a
SETQUOTA or GETQUOTA command. It includes the name of the quota
root, the resource limit in octets and the amount of resource
limit used.
4.9. Extensions
In order to simplify the process of extending the protocol, clients
MUST ignore unknown server responses which meet the syntax of
response-extend. In addition, clients MUST ignore server response
codes which meet the syntax of resp-code-ext. Availability of new
commands MUST be announced via a capability on the initial greeting
line and such commands SHOULD meet the syntax of command-extend.
Servers MUST respond to unknown commands with a BAD command
completion result. Servers MUST skip over non-synchronizing literals
contained in an extension command. This may be done by assuming the
unknown command matches the command-extend syntax, or by reading a
line at a time and checking for the non-synchronizing literal syntax
at the end of the line.
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5. Dataset Management
The entry with an empty name in the dataset is used to hold
management information for the dataset as a whole.
5.1. Dataset Inheritance
It is possible for a dataset to inherit data from another. Data in
the inherited dataset appears in the inheriting dataset, except where
explicitly overridden by data in the inheriting dataset.
The inherited dataset specifies which values may be overridden in the
inheriting datasets. If an inherited dataset has a non-NIL value for
any given attribute in an entry, the ACL for that attribute in that
entry must grant a user the 'o' right in order for the user to store
a corresponding value in an inheriting dataset.
The inherited dataset is usually a system-wide or group-wide set of
defaults. The system-wide dataset usually has one inheriting dataset
per user, allowing each user to add to or modify the defaults as
appropriate.
An entry which exists in both the inheriting and inherited dataset
has a modtime equal to the greator of the modtimes for the purposes
of a SEARCH command and context notification. Inheritance has no
effect on the STORE command other than that specified by the 'o'
right.
Servers MUST support at least two levels of inheritance. This
permits a user's dataset such as "/options/user/fred/common" to
inherit from a group dataset such as "/options/group/dinosaur
operators/common" which in turn inherits from a server-wide dataset
such as "/options/common/common".
5.2. Dataset attributes
The following attributes apply to management of the dataset when
stored in the "" entry of a dataset.
dataset.acl
This holds the default access control list for the dataset. It
can not be modified by the STORE command, only by the SETACL and
DELETEACL commands.
dataset.acl.<attribute>
This holds the default access control list for an attribute
within the dataset. It can not be modified by the STORE command,
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only by the SETACL and DELETEACL commands.
dataset.inherit
This holds the name of a dataset to inherit according to the
rules in section <section>.
6. Namespace conventions
6.1. Dataset Namespace
The dataset namespace is a slash-separated hierarchy. By convention,
the first component of the dataset namespace is a dataset class. A
dataset class SHOULD be published as an RFC which includes predefined
set of attributes and their meanings. The second component of the
dataset name is "common", "group", or "user" for server-wide, group-
wide, or per-user datasets respectively. For group or user datasets,
the third component of the dataset name is the name of the group or
the AUTHENTICATE identifier for the user. Other components of the
dataset name are specific to the dataset class.
Dataset classes MUST be registered with IANA according to the rules
in section <section>. Dataset classes which are intended for
interoperable use MUST be published as a standards track or IESG
approved experimental RFC.
6.2. Attribute Namespace
Attribute names which do not contain a dot (".") are reserved for
standardized attributes which have meaning in any dataset. In order
to simplify implementations, the attribute namespace is intended to
be unique across all datasets. To achieve this, attribute names are
prefixed with the dataset class name followed by a dot (".").
Attributes which effect management of the dataset are prefixed with
"dataset.". In addition, a subtree of the "vnd." or "prs."
namespaces may be registered with IANA according to the rules in
section <section>. ACAP implementors are encouraged to help define
interoperable dataset classes rather than using the private attribute
namespaces.
7. Registration procedures
ACAP's usefulness comes from providing a structured storage model for
all sorts of configuration data. However, for its potential to be
achieved, it is important that the Internet community strives for the
following goals:
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(1) Standardization. It is very important to standardize dataset
classes. The authors hope that ACAP achieves the success that SNMP
has seen with the definition of numerous standards track MIBs.
(2) Community Review. In the absence of standardization, it is
important to get community review on a proposal to improve the
engineering quality. Community review is strongly recommended prior
to registration. The ACAP developers mailing list <ietf-
acap@andrew.cmu.edu> may be used for this purpose.
(3) Registration. Registration serves a two-fold purpose. First it
prevents use of the same name for different purposes, and second it
provides a one-stop list which can be used to locate existing
extensions.
The following registration templates may be used to register ACAP
protocol elements.
7.1. Ordering Functions
Additional ordering functions may be registered with IANA on a
first-come, first-served basis. Ordering functions intended for
interoperable use SHOULD be defined as a standards track or IESG
approved experimental RFC.
To: XXX@XXX.XXX
Subject: Registration of new ACAP ordering function
Ordering name:
Scope: Any Dataset / Specific Dataset class / Specific locality
Published Specification(s):
(If the published specification is not standards track, or no
published specifiction is referenced then the ordering function is
assumed to be for limited use)
Person and email address to contact for further information:
7.2. ACAP Capabilities
New ACAP capabilities MUST be standards track or IESG approved
experimental RFCs. Registration provides a simple way to locate all
extensions. Careful consideration should be made before extending
the protocol, as it can lead to complexity or interoperability
problems.
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To: XXX@XXX.XXX
Subject: Registration of ACAP capability
Capability name:
Capability keyword:
Capability arguments:
standards track/IESG-approved experimental RFC number:
7.3. Dataset Classes
A dataset class provides a core set of attributes for use in a
specified hierarchy. It may also define rules for the dataset
hierarchy underneath that class. Community review of dataset classes
is strongly encouraged. Classes intended for interoperable use
should be written as standards track or IESG approved experimental
RFCs.
To: XXX@XXX.XXX
Subject: Registration of ACAP dataset class
Dataset class name/attribute prefix:
Purpose:
Required attributes:
Optional attributes:
Published Specification(s):
(The published specification must be freely available on the
Internet or included with the registration. It should include ABNF
[as defined in RFC 822] for the specified attributes.)
Person and email address to contact for further information:
7.4. Private Attribute Subtree
A private attribute subtree may be registered on a first come, first
serve basis. Private attributes may be used to store information
specific to a particular client within an ACAP entry of any dataset
class. Whenever possible, private attributes should be avoided in
favor of improving interoperable dataset class definitions.
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To: XXX@XXX.XXX
Subject: Registration of ACAP private prefix
Private Prefix: vnd.<company/product>. or prs.<person>.
Person and email address to contact for further information:
(company names and addresses should be included when appropriate)
8. Formal Syntax
The following syntax specification uses the augmented Backus-Naur
Form (BNF) notation as specified in [IMAIL] with one exception; the
delimiter used with the "#" construct is a single space (SPACE) and
not one or more commas.
Except as noted otherwise, all alphabetic characters are case-
insensitive. The use of upper or lower case characters to define
token strings is for editorial clarity only. Implementations MUST
accept these strings in a case-insensitive fashion.
ALPHA ::= "A" / "B" / "C" / "D" / "E" / "F" / "G" / "H" / "I" /
"J" / "K" / "L" / "M" / "N" / "O" / "P" / "Q" / "R" /
"S" / "T" / "U" / "V" / "W" / "X" / "Y" / "Z" /
"a" / "b" / "c" / "d" / "e" / "f" / "g" / "h" / "i" /
"j" / "k" / "l" / "m" / "n" / "o" / "p" / "q" / "r" /
"s" / "t" / "u" / "v" / "w" / "x" / "y" / "z" /
;; Case-sensitive
ATOM-CHAR ::= <any CHAR except ATOM-SPECIALS>
ATOM-SPECIALS ::= "(" / ")" / "{" / SPACE / CTL / QUOTED-SPECIALS
BASE64-CHAR ::= ALPHA / DIGIT / "+" / "/"
CHAR ::= <any 7-bit US-ASCII character except NUL, 0x01 - 0x7f>
CHAR8 ::= <any 8-bit octet except NUL, 0x01 - 0xff>
CR ::= <ASCII CR, carriage return, 0x0C>
CRLF ::= CR LF
CTL ::= <any ASCII control character and DEL, 0x00-0x1f, 0x7f>
DIGIT ::= "0" / DIGIT-NZ
DIGIT-NZ ::= "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9"
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LF ::= <ASCII LF, line feed, 0x0A>
OCTET ::= <any octet value 0x00 - 0xFF>
QUOTED-CHAR ::= <any TEXT-UTF8-CHAR except QUOTED-SPECIALS> /
"\" QUOTED-SPECIALS
QUOTED-SPECIALS ::= <"> / "\"
SPACE ::= <ASCII SP, space, 0x20>
TEXT-CHAR ::= <any CHAR except CR and LF>
TEXT-UTF8-CHAR ::= <any UTF8-CHAR except CR and LF>
UTF8-CHAR ::= <TODO: UTF-8 character>
acl-identifier ::= string
acl-object ::= "(" dataset [SPACE attribute [SPACE entry-name]] ")"
acl-rights ::= quoted
atom ::= 1*1024ATOM-CHAR
attribute ::= string
;; dot-separated attribute name
;; ends in ".bin" if value not textual
;; MUST NOT contain "*"
auth-type ::= atom
;; as defined in SASL [SASL]
base64-token ::= *(4BASE64-CHAR) [base64-terminal]
base64-terminal ::= (2BASE64-CHAR "==") / (3BASE64-CHAR "=")
command ::= tag SPACE (command-any / command-auth /
command-nonauth) CRLF
;; Modal based on state
command-authent ::= "AUTHENTICATE" SPACE atom [SPACE base64-token]
*(CRLF base64-token)
command-any ::= "NOOP"
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command-auth ::= command-delacl / command-dsince /
command-freectx / command-getquota /
command-lrights / command-myrights /
command-search / command-setacl /
command-setquota / command-store
;; only valid in authenticaticated state
command-delacl ::= "DELETEACL" SPACE acl-object [SPACE acl-identifier]
command-delete ::= "DELETE" SPACE entry-path
command-dsince ::= "DELETEDSINCE" SPACE dataset SPACE time
command-extend ::= atom [SPACE #extension-data]
command-freectx ::= "FREECONTEXT" SPACE context
command-getquota ::= "GETQUOTA" SPACE dataset
command-lrights ::= "LISTRIGHTS" SPACE acl-object
command-myrights ::= "MYRIGHTS" SPACE acl-object
command-nonauth ::= command-authent
;; only valid in non-authenticated state
command-search ::= "SEARCH" SPACE (dataset / context)
*(SPACE search-modifier)
SPACE search-criteria
command-setacl ::= "SETACL" SPACE acl-object SPACE acl-identifier
SPACE acl-rights
command-setquota ::= "SETQUOTA" SPACE quota-root SPACE (number / nil)
command-store ::= "STORE" SPACE 1#store-entry
context ::= string
;; MUST NOT begin with slash ("/")
continue-req ::= "+" SPACE (resp-text / base64-token)
dataset ::= string
;; slash-separated dataset name
;; begins with slash
entry ::= entry-name / entry-path
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entry-name ::= string
;; entry name MUST NOT contain slash
;; MUST NOT begin with "."
entry-path ::= string
;; slash-separated path to entry
;; begins with slash
entry-relative ::= string
;; potentially relative path to entry
extension-data ::= string / number / "(" #extension-data ")"
initial-greeting ::= "*" SPACE "ACAP" *(SPACE init-capability) CRLF
init-capability ::= atom [ "(" 1#string ")" ]
literal ::= "{" number [ "+" ] "}" CRLF *OCTET
;; The number represents the number of octets
;; MUST be literal-utf8 except for values of
;; attributes whose names end in ".bin"
literal-utf8 ::= "{" number [ "+" ] "}" CRLF *UTF8-CHAR
;; The number represents the number of octets
metadata ::= attribute [ "(" 1#metadata-type ")" ]
metadata-partial ::= "value<" number "." number ">"
metadata-store ::= 1#(attribute ["(" metadata-write ")"] SPACE
nstring)
metadata-type ::= "acl" / "attribute" / "myrights" / "size" /
metadata-partial / metadata-write
metadata-write ::= "value"
nil ::= "NIL"
nstring ::= nil / string
number ::= 1*DIGIT
nz-number ::= DIGIT-NZ *DIGIT
ordering ::= ("+" / "-") atom
quota-root ::= dataset
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quoted ::= <"> *QUOTED-CHAR <">
response ::= *response-data response-done
response-addto ::= "*" SPACE "ADDTO" SPACE context SPACE entry-name
SPACE number SPACE #return-data
response-bye ::= "*" SPACE "BYE" SPACE resp-body CRLF
;; Server will disconnect condition
response-change ::= "*" SPACE "CHANGE" SPACE context SPACE entry-name
SPACE number SPACE number SPACE #return-data
response-data ::= response-change / response-deleted /
response-entry / response-implic /
response-mtimei / response-mtimeu /
response-myright / response-refer /
response-remove / response-stat / response-bye
response-deleted ::= tag SPACE "DELETED" SPACE entry-name
response-done ::= tag SPACE resp-cond-state CRLF
response-entry ::= tag SPACE "ENTRY" SPACE entry SPACE #return-data
response-extend ::= tag SPACE atom [SPACE 1#extension-data]
response-implic ::= tag SPACE "LISTRIGHTS" SPACE acl-rights
0*(SPACE acl-rights)
response-mtimei ::= tag SPACE "MODTIME" SPACE time
response-mtimeu ::= "*" SPACE "MODTIME" SPACE context SPACE time
response-myright ::= tag SPACE "MYRIGHTS" SPACE acl-rights
response-refer ::= tag SPACE "REFER" SPACE dataset SPACE
<"> url-relative <">
response-remove ::= "*" SPACE "REMOVEFROM" SPACE context SPACE
entry-name SPACE number
response-stat ::= "*" SPACE resp-cond-state CRLF
resp-body ::= ["(" resp-code ")" SPACE] quoted
Newman [Page 49]
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resp-code ::= "ALERT" / "MODIFIED" / "PERMISSION" / "QUOTA" /
resp-code-refer / resp-code-many /
"TRYFREECONTEXT" / resp-code-ext
resp-code-ext ::= atom [SPACE 1#extension-data]
;; extension-data MUST NOT contain "]"
resp-code-many ::= "TOOMANY" SPACE nz_number
resp-code-refer ::= "REFER" SPACE 1#(<"> url-relative <">)
resp-cond-state ::= ("OK" / "NO" / "BAD") SPACE resp-body
;; Status condition
return-data ::= nstring / number
searchkey-equal ::= "EQUAL" SPACE attribute SPACE ordering SPACE value
searchkey-comp ::= "COMPARE" SPACE attribute SPACE ordering SPACE value
searchkey-strict ::= "COMPARESTRICT" SPACE attribute SPACE ordering
SPACE value
searchkey-range ::= "RANGE" SPACE nz-number SPACE nz-number
SPACE time
searchmod-depth ::= "DEPTH" SPACE number
searchmod-hard ::= "HARDLIMIT" SPACE nz-number
searchmod-limit ::= "LIMIT" SPACE number SPACE number
searchmod-make ::= "MAKECONTEXT" SPACE context
searchmod-notify ::= "NOTIFYCONTEXT"
searchmod-return ::= "RETURN" SPACE "(" #metadata ")"
searchmod-sort ::= "SORT" SPACE "(" 1#(attribute SPACE ordering) ")"
search-criteria ::= "ALL" / searchkey-equal / searchkey-comp /
searchkey-strict / searchkey-range /
"NOT" SPACE search-criteria /
"OR" SPACE search-criteria SPACE search-criteria /
"AND" SPACE search-criteria SPACE search-criteria
Newman [Page 50]
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search-modifier ::= searchmod-depth / searchmod-hard /
searchmod-limit / searchmod-make /
searchmod-notify / searchmod-return /
searchmod-sort
store-cond ::= SPACE "UNCHANGEDSINCE" SPACE time
store-entry ::= "(" entry-path [store-cond]
*(SPACE metadata-store) ")"
string ::= quoted / literal
tag ::= 1*<any ATOM-CHAR except "+" or "*">
time ::= <"> time-year time-month time-day time-hour
time-minute time-second time-subsecond <">
time-day ::= 2DIGIT ;; 00-31
time-hour ::= 2DIGIT ;; 00-23
time-minute ::= 2DIGIT ;; 00-59
time-month ::= 2DIGIT ;; 01-12
time-second ::= 2DIGIT ;; 00-60
time-subsecond ::= *DIGIT
time-year ::= 4DIGIT
value ::= nstring
url-acap ::= "acap://" url-server "/" url-enc-entry [url-filter]
;; url-enc-entry interpreted relative to "/"
url-attr-list ::= url-enc-attr *("&" url-enc-attr)
url-auth ::= ";AUTH=" ("*" / auth-type)
url-achar ::= uchar / "&" / "=" / "~"
;; See RFC 1738 for definition of "uchar"
url-char ::= uchar / "=" / "~" / ":" / "@" / "/"
;; See RFC 1738 for definition of "uchar"
url-depth ::= "DEPTH=" number
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url-enc-attr ::= 1*url-char
;; encoded version of attribute name
url-enc-auth ::= 1*url-achar
;; encoded version of auth-type above
url-enc-entry ::= 1*url-char
;; encoded version of entry-relative above
url-enc-search ::= 1*url-char
;; encoded version of search-criteria above
url-enc-user ::= *url-achar
;; encoded version of login userid
url-filter ::= "?" url-attr-list ["?" url-depth ["?" url-enc-search]]
url-relative ::= url-acap / [url-enc-entry] [url-filter]
;; url-enc-entry is relative to base URL
url-server ::= [url-user [url-auth] "@"] hostport
;; See RFC 1738 for definition of "hostport"
Newman [Page 52]
Internet DRAFT ACAP March 26, 1997
9. Security Considerations
ACAP protocol transactions, including address book and option data,
are sent in the clear over the network unless the optional privacy
protection is negotiated in the AUTHENTICATE command.
Additional security considerations are discussed in the section
discussing the AUTHENTICATE command.
10. Authors' Addresses
Chris Newman
Innosoft International, Inc.
1050 East Garvey Ave. South
West Covina, CA 91790 USA
Email: chris.newman@innosoft.com
John G. Myers
Email: jgm+@cmu.edu
Newman [Page 53]
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Appendices
A. References
[IMAP4] Crispin, M., "Internet Message Access Protocol - Version
4rev1", RFC 2060, University of Washington, December 1996.
<ftp://ds.internic.net/rfc/rfc2060.txt>
[IMAP-ACL] Myers, J., "IMAP4 ACL extension", RFC 2086, Carnegie
Mellon, January 1997.
<ftp://ds.internic.net/rfc/rfc2086.txt>
[SASL] Myers, J., "Simple Authentication and Security Layer (SASL)",
draft-myers-auth-sasl-xx.txt
[IMAIL] Crocker, D., "Standard for the Format of ARPA Internet Text
Messages", STD 11, RFC 822, University of Delaware, August 1982.
<ftp://ds.internic.net/rfc/rfc822.txt>
[UTF8] Yergeau, F. "UTF-8, a transformation format of Unicode and ISO
10646", RFC 2044, Alis Technologies, October 1996.
<ftp://ds.internic.net/rfc/rfc2044.txt>
[US-ASCII] "USA Standard Code for Information Interchange," X3.4.
American National Standards Institute: New York (1968).
[BASIC-URL] Berners-Lee, Masinter, McCahill, "Uniform Resource
Locators (URL)", RFC 1738, CERN, Xerox Coproration, University of
Minnesota, December 1994.
<ftp://ds.internic.net/rfc/rfc1738.txt>
[REL-URL] Fielding, "Relative Uniform Resource Locators", RFC 1808,
UC Irvine, June 1995.
<ftp://ds.internic.net/rfc/rfc1808.txt>
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B. ACAP Keyword Index
ACAP (untagged response) ................................... 19
ADDTO (untagged response) .................................. 31
ALERT (response code) ...................................... 16
ALL (search keyword) ....................................... 28
AND (search keyword) ....................................... 28
AUTHENTICATE (command) ..................................... 23
BAD (response) ............................................. 22
BYE (untagged response) .................................... 22
CHANGE (untagged response) ................................. 32
COMPARE (search keyword) ................................... 28
COMPARESTRICT (search keyword) ............................. 28
CONTEXTLIMIT (ACAP capability) ............................. 20
DELETEACL (command) ........................................ 37
DELETED (intermediate response) ............................ 34
DELETEDSINCE (command) ..................................... 34
DEPTH (search modifier) .................................... 25
ENTRY (intermediate response) .............................. 29
EQUAL (search keyword) ..................................... 28
FREECONTEXT (command) ...................................... 30
GETQUOTA (command) ......................................... 40
HARDLIMIT (search modifier) ................................ 26
IMPLEMENTATION (ACAP capability) ........................... 20
LIMIT (search modifier) .................................... 26
LISTRIGHTS (command) ....................................... 38
LISTRIGHTS (intermediate response) ......................... 38
LOGOUT (command) ........................................... 21
MAKECONTEXT (search modifier) .............................. 26
MODIFIED (response code) ................................... 16
MODTIME (intermediate response) ............................ 29
MODTIME (untagged response) ................................ 32
MYRIGHTS (command) ......................................... 37
MYRIGHTS (intermediate response) ........................... 38
NO (response) .............................................. 21
NOOP (command) ............................................. 20
NOT (search keyword) ....................................... 28
NOTIFYCONTEXT (search modifier) ............................ 26
OK (response) .............................................. 21
OR (search keyword) ........................................ 28
ORDERINGS (ACAP capability) ................................ 20
PERMISSION (response code) ................................. 17
QUOTA (intermediate response) .............................. 40
QUOTA (response code) ...................................... 17
RANGE (search keyword) ..................................... 28
REFER (intermediate response) .............................. 29
REFER (response code) ...................................... 17
REMOVEFROM (untagged response) ............................. 31
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RETURN (search modifier) ................................... 27
SASL (ACAP capability) ..................................... 20
SEARCH (command) ........................................... 25
SETACL (command) ........................................... 36
SETQUOTA (command) ......................................... 39
SORT (search keyword) ...................................... 27
STORE (command) ............................................ 33
TOOMANY (response code) .................................... 17
TRYFREECONTEXT (response code) ............................. 17
UNCHANGEDSINCE (STORE modifier) ............................ 33
UPDATECONTEXT (command) .................................... 30
WAYTOOMANY (response code) ................................. 17
acl (attribute metadata) ................................... 11
anyone (ACL identifier) .................................... 34
attribute (attribute metadata) ............................. 11
dataset.acl (dataset attribute) ............................ 41
dataset.acl.<attribute> (dataset attribute) ................ 41
dataset.inherit (dataset attribute) ........................ 42
en-nocase (ordering function) .............................. 16
entry (predefined attribute) ............................... 9
modtime (predefined attribute) ............................. 9
myrights (attribute metadata) .............................. 11
numeric (ordering function) ................................ 16
octet (ordering function) .................................. 15
size (attribute metadata) .................................. 11
subdataset (predefined attribute) .......................... 10
value (attribute metadata) ................................. 11
value<ORIGIN.SIZE> (attribute metadata) .................... 11
Newman [Page 56]
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